A sheet-feeding cassette such as that disclosed in, e.g., JP-A-1-209227 (FIGS. 11 and 12), has hitherto been provided as a sheet-feeding cassette for use in an image forming apparatus such as a laser printer. According to this technique, a cassette main body 21a of a sheet cassette has sawtooth-shaped recess sections 84 used for regulating the position of a sheet guide 82, and recesses 88 corresponding to widths of sheets of standardized sizes. The sheet guide 82 is provided with wedge-shaped engagement pieces 85 capable of engaging with the recess sections 84 of the cassette main body 21, and protuberances 89 capable of engaging with the recesses 88. During movement of the sheet guide, the cassette main body is lifted so as to disengage the recess section 84 from the engaging piece 85, whereby the position of the sheet guide is adjusted.